Cellular and Molecular Genetics

Question 1

what are 3 components of mendelian genetics?

Answer 1

• selection and transmission of genes
• dominance and gene expression
• genotypic basis of phenotypic outcomes

Question 2

what are 4 components of molecular and cellular genetics?

Answer 2

• gene structure
• DNA as a blueprint
• DNA replication and error correction
• the cell cycle and genetic recombination

Question 3

what is a gene?

Answer 3

• a region of DNA that controls a discrete hereditary characteristic, usually corresponding to a single protein or RNA.
• this encompasses the entire functional unit, including coding DNA sequences, noncoding regulatory regions, and introns

Question 4

DNA is organized into ___

Answer 4

chromosomes

Question 5

the genome is constructed of ___ chromosomes.

Answer 5

46

44 autosomes (22 pairs) and 2 sex chromosomes (1 pair)

Question 6

DNA to RNA describes what?

Answer 6

transcription

Question 7

RNA to protein describes what?

Answer 7

translation

Question 8

DNA is wrapped around ___ to form nucleosomes

Answer 8

histones

Question 9

eukaryotic DNA exists in long ___ strands

Answer 9

linear

Question 10

DNA in nucleosome form is called ___

Answer 10

chromatin

Question 11

draw out the cell cycle

Answer 11

• check points at the end of G1 and G2

Question 12

what is LINE?

Answer 12

• long interspersed nuclear elements
• thought to be involved in gene silencing and regulation

Question 13

what is SINE?

Answer 13

• short interspersed nuclear elements
• thought to be involved in gene silencing and regulation

Question 14

during what phase is DNA replicated?

Answer 14

synthesis (S) phase

Question 15

in the S phase, replication initiates at ___ origins, both DNA strands are ___, and DNA replication is ___

Answer 15

• replication
  
  • replication bubbles are formed
  • replication occurs in both directions
• templates
• semiconservative

Question 16

in the S phase, DNA replication is semiconservative. what does that mean?

Answer 16

each of the two strands from the original “parent” DNA double helix serve as templates for a new strand

Question 17

DNA is synthesized at ____

Answer 17

replications forks

Question 18

in eukaryotic replication fork synthesis, what makes up the primosome?

Answer 18

DNA helicase and DNA primase

Question 19

what holds together two chromatids to make a chromosome?

Answer 19

the centromere

Question 20

what does DNA polymerase do?

Answer 20

polymerizes new DNA strands

Question 21

what does topoisomerase do?

Answer 21

places nicks in the DNA to relax coils

Question 22

what does DNA primase do?

Answer 22

creates RNA primers on the lagging strand

Question 23

DNA polymerase replicates DNA, and chain growth occurs in what direction?

Answer 23

5’ to 3’

so, all of the base pairs are added to the 3’ end

Question 24

what are the functions of polymerase alpha, beta, gamma, delta, and epsilon?

Answer 24

• alpha - RNA and/or DNA primers
• beta - base-excision repair
• gamma - mitochondrial DNA replication and repair
• delta - lagging-strand synthesis, DNA repair
• epsilon - leading-strand synthesis

Question 25

what are 4 common DNA damages?

Answer 25

* mismatch * deamination * depurination * double strand break

Question 26

eukaryotic cells divide by ___ and \_\_\_

Answer 26

mitosis and meiosis (in that order)

Question 27

draw out the mitosis phase

Answer 27

Question 28

draw out the meiosis phase

Answer 28

Question 29

the completion of interphase leads to \_\_\_

Answer 29

mitosis

Question 30

what 3 things happen during interphase?

Answer 30

* the cell increases in size * DNA of the chromosomes is replicated * the centrosome is duplicated

Question 31

what happens in the G1, S, and G2 phases of the cell cycle?

Answer 31

* G1 - protein synthesis, checkpoint * S - DNA replication * G2 - protein synthesis, checkpoint

Question 32

what occurs in the prophase step of mitosis?

Answer 32

* chromosomes condense * mitotic spindle assembles

Question 33

what occurs in the prometaphase step of mitosis?

Answer 33

* nuclear envelope breaks down * chromosomes attach to spindle via kinetocore, and undergo movement

Question 34

what occurs during the metaphase step of mitosis?

Answer 34

* chromosomes align along the equator of the spindle between the poles * kinetocore microtubules attach sister chromatids to opposite poles of the spindle

Question 35

what occurs during the anaphase step of mitosis?

Answer 35

* sister chromatids separate to form two daughter chromosomes which move toward opposite poles * kinetochore microtubules get shorter; spindle poles move apart * chromosome separation

Question 36

what occurs during the telophase step of mitosis?

Answer 36

* daughter chromosomes arrive at spindle poles and decondense * nuclear envelope reassembles around individual chromosomes * cytoplasm division begins and contractile ring starts to form

Question 37

what occurs during the cytokinesis step of mitosis?

Answer 37

* cytoplasm is divided in two by the contractile ring * actin and myosin filaments * contractile ring pinches the cell in two, creating two new daughter cells

Question 38

meiosis forms ___ gametes

Answer 38

haploid (1n)

Question 39

what are 4 characteristics of meiosis?

Answer 39

* additional round of division * genetic reassortment * bivalents form during meiosis I * genetic recombination occurs within bivalents in meiosis I

Question 40

chromosome assortment increases \_\_\_

Answer 40

genetic diversity

Question 41

general recombination exchanges ___ and ___ genetic content

Answer 41

maternal and paternal

Question 42

recombination is directed by \_\_\_

Answer 42

recombinases

Question 43

diploid starting cell: two different chromosome assortment patterns meiosis I yields how many diploid cells? meiosis II yields how many haploid cells? what does this describe?

Answer 43

* 4 * 8 * independent assortment

Question 44

describe recombination

Answer 44

* increases genetic diversity * maternal and paternal chromosomes cross over and swap genetic information * they then undergo independent assortment

Question 45

chromosome assortment increases genetic diversity in what two ways?

Answer 45

independent assortment and recombination

Question 46

general recombination occurs in bivalent chromosomes. what does this mean?

Answer 46

* pairing of duplicated homologous chromosomes forms a bivalent * two kinetocores sit next to each other/ line up on the spindle * recombination occurs * genetic material is swapped

Question 47

transposable elements create \_\_\_

Answer 47

site-specific recombination

Question 48

what are the 3 classes of transposable elements?

Answer 48

* DNA-only transposons * retroviral-like retrotransposons * nonretroviral retrotransposons

Question 49

age and genetic lineage can be traced by what?

Answer 49

identifying and locating transposons

Question 50

what is the general function of retroviral-like retrotransposons and nonretroviral retrotransposons?

Answer 50

* produce RNA transcript, which is then put back into the genome as a DNA transcript * undergoes an RNA intermediate

Question 51

what is the cut-and-paste process of transposon insertion?

Answer 51

transposon is physically removed from DNA

Question 52

what is the viral insertion process of transposon insertion?

Answer 52

viral DNA attacks particular region, integrates it into that portion of the DNA

Question 53

what is the replication process of transposon insertion?

Question 54

how are recombined chromosomes segregated?

Answer 54

* sister chromatids start to pull apart * meiotic metaphase I * arms of sister chromatids become unglued * meiotic anaphase I * brief interphase followed by m-phase with kinetochores functioning separately on each sister chromatid * meiotic metaphase II * sudden detachment of chromosomes (sister chromatids) at centromere * meiotic anaphase II genetic structure is altered

Question 55

when are tetrads formed?

Answer 55

during metaphase I (meiosis I)